Ladder assembly



P 16, 1969 R. s. FRAUENHOFF 3,467,219

LADDER ASSEMBLY Filed Nov. 22, 1968 INVENTOR RICHARD E. FRAUENHOFF BY/ To i I 9 2 a ATTORNEYS United States Patent 3,467,219 LADDER ASSEMBLYRichard E. Frauenhotf, Montgomery, Ill., assignor to Caterpillar Tractor(30., Peoria, 111., a corporation of California Filed Nov. 22, 1968,Ser. No. 778,151 Int. (ll. E06c 9/02, 7/08; A62b 1/20 US. Cl. 18293 3Claims ABSTRACT OF THE DISCLOSURE A ladder assembly for arrangement onthe side of a structure to provide access onto the structure has asupport member and means for securing it to the structure. A pluralityof steps arranged at intervals along the support member each include apair of angularly related, elongated plates presenting a pair ofupwardly facing, spaced apart angular edges as a stepping surface.

The present invention relates to a novel ladder assembly to provideaccess onto a structure. The ladder assembly is particularly adaptablefor use on large vehicles such as earthmoving machinery. Ladderassemblies in the prior art for use on structures of the typecontemplated by the present invention normally have steps formed witheither round or flat bearing surfaces which tend to become slippery whenWet or muddy. Even though the steps are commonly formed with antiskidsurfaces, they tend to retain mud or other matter so that personnelemploying the ladders may encounter unsafe footing.

It is accordingly an object of the present invention to provide a ladderassembly having stepping surfaces which continually provide firm footingregardless of weather conditions.

Other objects and advantages of the invention are made apparent in thefollowing description having reference to the accompanying drawing.

In the drawing:

FIG. 1 is a view in elevation of the ladder assembly as it would appearin place on the side of a structure,

FIG. 2 is a side View of the ladder assembly of FIG. 1;

FIG. 3 is a cross-sectional view of one of the steps in the ladder; and

FIG. 4 is a view taken along section line IVIV of FIG. 1.

Referring now to the drawing, the ladder assembly of the presentinvention includes a plurality of steps 11 secured at suitable intervalsto a structural support member 12 shown in cross-section by FIG. 4. Thesupport member 12 has a pair of struts 13 and 14 for securing thesupport member 12 to the side of a vehicle or other structure. Thestruts 13 and 14 include mounting brackets 16 and 17. The struts 13 and14 are preferably of unequal lengths so that the support member 12 maybe mounted at an incline from a vertical plane and support the steps 11along the same incline.

Each of the steps 11 includes a pair of elongated plates 18 and 19 whichare cantilevered in spaced apart relation at intervals along the supportmember 12. The plates 18 and 19 extend upwardly in angular relation tohave a stepping surface formed by angular edges 21 and 22 of "ice theplates 18 and 19 respectively. The plates 18 and 19 are preferablyangled along their lengths, as best seen in FIG. 3, so that the lowerportions of the plates 18 and 19 are spaced further apart than theirupper edges 21 and 22. In this manner, the edges 21 and 22 tend tocontinually provide a good bearing surface for personnel using theladder. The absence of level surfaces on the steps 11 tends to preventthe retention of water, mud, rock or other material which mightotherwise deleteriously affect the footing provided by the steps. Theangular relation of the plates 18 and 19 prevents mud or other materialfrom being wedged within the central opening of each of the steps.

A guard member 23 is secured to the free end of the cantilevered plates18 and 19 of the step and extends above the edges 21 and 22 to preventan operators foot from slipping olf the end of the steps. The guardmembers 23 are preferably formed from arched rods so that the openingbetween the plates 18 and 19 is maintained along the cantilevered lengthof each of the steps.

The present invention accordingly provides a ladder assembly includingsteps having an improved nonslip bearing surface formed by the angularedges 21 and 22 of the plates 18 and 19. As an operator mounts thesteps, the edges tend to grip his shoe sole and prevent slippage. Asnoted above, the absence of fiat surfaces tends to prevent the retentionof water, mud or rocks while the configuration of the plates 18 and 19tends to permit self cleaning of the steps and provide improved footingin all kinds of weather.

What is claimed is:

1. A ladder assembly for disposition on the side of a structure toprovide means for mounting and dismounting from the structure,comprising a support member and means for securing it in a genarallyvertical plane and a plurality of steps arranged at intervals along thesupport member, each step including a pair of spaced apart, elongatedplates extending angularly upwardly toward each other along the lengthof the step and presenting a pair of upwardly facing, spaced apartangular edges as a stepping surface.

2. The invention of claim 1 wherein the plates forming each step arecantilevered from the support member with a guard member joining thefree ends of the plates and extending upwardly from the stepping surfaceformed by the plates.

3. The invention of claim 2 wherein each of the step plates is angularlyformed along its length and the guard members are arched rods tomaintain a spaced opening for each step along its cantilevered length.

References Cited UNITED STATES PATENTS 627,893 6/1899 Becker l82189646,291 3/1900 Krueger l82189 2,143,783 l/1939 Liebman l82228 2,583,836l/l952 Gruetjen l82-93 REINALDO P. MACHADO, Primary Examiner US. Cl.X.R. 182-189, 228

